RFR: 8299240: rank of JvmtiVTMSTransition_lock can be safepoint [v2]

[Serguei Spitsyn]

> The rank of JvmtiVTMSTransition_lock is better to be safepoint instead of nosafepoint.
> The fix includes removal of the function `check_vthread_and_suspend_at_safepoint` which is not needed anymore.
> 
> Testing:
> mach5 jobs are in progress:
>  Kitchensink, tiers1-6 (all JVMTI, JDWP, JDI and JDB tests have to be included)

Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:

  addressed review comments from Coleen

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/12550/files
  - new: https://git.openjdk.org/jdk/pull/12550/files/e408826e..244836dc

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12550&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12550&range=00-01

  Stats: 7 lines in 1 file changed: 2 ins; 2 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/12550.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12550/head:pull/12550

PR: https://git.openjdk.org/jdk/pull/12550